Method of locating water and gaseous fluid stratas in well bores



Aug. 30, 1949. H. .1. EASTMAN METHOD OF LOCATING WATER AND GASEOUS FLUIDSTRATAS IN WELL BORES Filed May .8, 1944 Haflan Jolm Easfmcm INV ENTORfiz/IiJm/A ATTORNEY Patented Aug. 30, 1949 UNITED STATES PATENT OFFICEMETHOD OF LOCATING WATER AND GASE- OUS FLUID STRATAS IN WELL BORESHarlan John Eastman, Denver, (3010., assignor to Eastman Oil Well SurveyCompany, Denver, 0010., a corporation of Delaware Application May 8,1944, Serial No. 534,680

12 Claims. (Cl. 73-155) i viously because the water, gaseous fluid andoil are thoroughly admixed with each other when brought to the surface,it is impossible to determine at what elevation the water and gaseousfluid entered the fluid column. The ingress of water int the well boreis undesirable and it is necessary to determine the exact point of suchingress in order that a sealing off, by cement or other means, of thewater strata may be effected. The gaseous fluid which enters the boreis, because of its pressure, desirable since it aids in flowing the oilinto the well bore and for this reason, it is advantageous to know thepoint of entry of the gaseous fluid into the well bore so that the entryof such fluid will not be restricted when the water strata is sealedoff. Various methods of locating the point of ingress of water into awell bore have been devised but all such methods involve the measurementof one or more electrical properties of the fluid column in the wellbore.

The salt or saline water which enters the well bore from its strata hasa higher temperature than the oil flowing into said bore whereby at thepoint of entry of the salt water into said bore, a high temperature zoneis created. Gas or gaseous fluid on the other hand will expand as itenters the well bore from its strata and such expansion will result inthe creation of a cool zone within the bore, this cool zone beinglocated within the well bore opposite the point of entry of the gas orfluid. The present invention contemplates a method wherein thesetemperature zones are utilized to indicate the location or elevation ofthe water and gas stratas traversed by the well bore.

For the purpose of this description .the term gas will be usedthroughout and by this term is meant either gas as it is found in wellbores or any hydrocarbon or otherfluid which enters the well bore in agaseous state.

One object of the invention is to provide a simple and improved methodwhereby the exact elevation or point of entry of water, as well asgaseous fluid, into a well bore may be positively ajngi accuratelydetermined in a minimum length 0 me.

A particular object of the invention is to pro vide an improved method,of the character described, wherein temperature recording apparatus islowered through the well fluid column, whereby the natural highertemperature zone created by the entry of water and the coolertemperature zone created by the entry of gas may be accurately locatedto indicate the point of ingress of such water and gas into said wellbore.

Another object of the invention is to provide an improved method of thecharacter described which consists in first artificially changing thenormal temperature of the fluid column in the well either by heating orcooling said column, and then taking temperature recordings throughoutthe fluid column; whereby the hotter zones caused by entry of salt waterinto the well bore and the cooler zones created by the entry of gas intosaid bore may be more readily located by means of said temperaturemeasuring apparatus.

A particular object of the invention is to provide an improved method oflocating the point of entry of salt water and gas into a well bore whichincludes the steps of first removing a portion of the normal well fluidcolumn which stands in the well bore, such removal of said portion beingfrom the top of the column so as to prevent disturbance of the remainderof said fluids, then permittin the column to return to its normal levelwhich is caused by the entry of additional fluids from the formations,and then taking continuous temperature readings throughout the column toascertain the difierent temperature zones created by the entry of saltwater and gas into said bore which were caused to flow intothe bore bythe first step of lowering of the normal standing liquid level.

Still another object of the invention is to provide an improved method,of the character described, wherein the artificial change of temperatureof thefluid column may be utilized in connection with the lowering ofthe standing liquid level so that the temperature zones created by theentry of the water and gas are more easily detected.

A still further object of the invention is to provide a method which ispreferably continuous, that is, the steps thereof, are carried out asrapidly as possible so that the temperature zones which are to bedetected are not dissipated before the temperature measurements aremade; also, the steps of said method may be repeated as many times asdesirable in order to not only locate the point of entry but also toindicate the volume of water or gas entering at such point.

The method contemplates the use of any suitable artificial heating orcooling means and also the use of any suitable continuous temperaturerecording apparatus.

The construction designed to carry out the invention will be hereinafterdescribed together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawing,wherein an example of the invention is shown, and wherein:

Figure 1 is a transverse, vertical sectional view of a' well boreillustrating the various underground stratas traversed by said bore,

Figure 2 is a diagrammatic view, showing a cooling unit being loweredthrough the column to change its temperature,

Figure 2A is a view similar to Figure 2 and illustrating a heating pipelowered within the well,

Figure 3 is a diagrammatic view, showing the normal standing fluid levelof the well being lowered by means of an ordinary bailer,

Figure is a similar view illustrating the lowering of a temperaturemeasuring apparatus through the fluid column which has risen back to itsnormal standing level,

Figure 5 is a view of a portion of the temperature recording chart ofthe measuring apparatus, and

Figure 6 is a view similar to Figure 5 showing another indication on thechart.

In the drawings, the numeral l0 designates a well bore which has theusual well casing H extending downwardly therein. As is the usualpractice the lower end of the casing is cemented in place, as indicatedby the cement 62. A perforated oil inlet pipe I3 extends downwardly fromthe casing and the well fluids enter the well bore through theperforation of said pipe, said fluids rising upwardly in the well casingto the normal I This standing standing liquid level of the well. liquidlevel, indicated at L in the drawings, will of course vary in accordancewith particular well conditions.

The various subterranean stratas which are traversed by a well bore aredependent upon the particular area in which said well bore is locatedand merely for the purpose of illustration, the well bore i!) is shownas having a water strata A behind the well casing It, a second waterstrata B opposite the inlet pipe IS, a gas strata C also adjacent saidpipe and an oil sand or producing formation D at the lower end of thewell bore. The water from the strata A will flow downwardly along theoutside of the well casing H and cement anchor and will enter the wellbore at the lower end of said casing; water from area B and gas from thestrata C will flow into the bore at the elevations opposite said areaand said strata while the oil will enter at the lower end of the boreopposite the producing formation D. These well fluids will difl'use andadmix with each other and will rise to the normal standing level L ofthe well. The longer said fluids are permitted to stand in the well boreundisturbed, the more diflicult it becomes to determine the point ofentry of the various constituents because manifestly, the water willtend to settle downwardly while the gas and oil will tend to rise abovethe water. Therefore although it is readily apparent that water and gasare present in the fluid column, it is impossible to know at whatelevation tsJaicl water and gas originally entered the well ore.

As has been stated, the water which enters a well bore from anunderground strata is salt water and it has been proven that this saltwater has a higher temperature in situ than oil. From this it followsthat when the salt water first enters the well bore it creates a hightemperature zone within the bore and immediately adjacent its point ofentry. This zone remains within the bore until sufiicient diffusion oradmixture of the water with the other well fluids has occurred to bringabout an equalization of temperatures.

In contrast to the higher temperature zone created by the entry of saltwater into a well fluid column, gas flowing from a subterranean stratainto a well bore will expand upon entering said bore, such expansionbeing caused by the reduction in pressure as the gas enters the bore.This expansion of the incoming gas creates a cooler zone in the bore andmanifestly, such zone will be adjacent the point of entry. Until thelapse of suflicient time to permit dissipation of the cooler zone, saidzone will be apparent in the fluid column.

In carrying out the present invention, a temperature measuring apparatusi5 is adapted to be lowered through the fluid column on the usualelectrical conductor cable 16 (Figure 4).

The apparatus may be of any of the well known types now in use fordetermining the temperature of well fluids within a bore hole and iscapable of continuous recording. The electrical conductor cable 16 haselectrical connection with and actuates a surface recording apparatus i!which includes a movable tape 18 and stylus l9 (Figure 5). The stylus iscontrolled by the measuring apparatus which is lowered through the wellfluids and obviously any change in fluid temperature as measured by themeasuring apparatus is visibly recorded on the tape by the indicatingline 20 made by the stylus.

The apparatus I5 is first lowered through the fluid column and thenormal temperature of said column is recorded on the tape. Thisinformation indicates the temperature of the fluid column throughout itslength under normal dormant conditions and after the diffusion oradmixture of all of the constituents making up said column. Ordinarilythis temperature will be fairly constant because the various differenttemperatures of the water, gas and oil have had suificient time toequalize themselves.

After the normal temperature of the fluid column is obtained, themeasuring apparatus 15 is withdrawn and a bailer 2| is lowered in theusual manner on a wire line or cable 22. The bailer is employed toremove a portion of the liquid column, such removal being from the upperend of said column whereby the remainder of the column is undisturbed.This bailing operation lowers the level of the fluid column from thepoint L, its normal level to some point therebelow as indicated by M.Preferably the level is lowered only a few feet but obviously thediameter of the well bore, the height of the normal level and otherfactors must be considered so that the distance which the normal levelis lowered by the bailing operation is actually dependent uponindividual well conditions.

When the normal standing level of the fluid column is lowered, thenatural function of the column to again seek its normal level will causeadditional well fluids to enter the bore. This means that water willenter at the extreme lower end of the casing II and also opposite thestrata B while gas will flow into said bore adjacent its strata C. Oilwill enter from the formation D at the lower portion of the bore. Asexplained, the water is of a higher temperature and will create hightemperature zones AA and BB at its point of entry whereas the gas willcreate a cool zone CC at the point adjacent its entry.

As soon as the normal level L of the well is again attained, or evenbefore such level is reached provided'additional water and gas hasentered the bore, the temperature measuring apparatus is again loweredthrough the fluid column. The previous temperature recording apparatushas given the operator the normal temperature of the column and thus solong as the recording apparatus indicates this normal or basetemperature, the operator is advised that the apparatus I is movingthrough the fluid which was present in'the bore upon the previous run.However, as soon as the apparatus l5 enters the higher temperature zoneAA, this higher temperature is recorded by an offset 22 in the recordingline (Figure'5) thereby indicating the presence of such zone. Therecording tape I8 is synchronized with the lowering of the cable I6 sothat the exact elevation in feet of the zone AA is indicated. Since thehigher temperature zone AA is created by the entrance of salt water intothe fluid column the exact point of ingress of the water is therebydetermined.

As the apparatus moves downwardly out of the zone AA and into the fluidcolumn, the temperature is again the normal or base temperature and isso indicated by the stylus and tape. Upon entry into the second zone BB,the meas uring apparatus I 5 again actuates the recorder to form asecond offset 23 in the indicating line to indicate the presence andlocation of said zone, whereby the operator is advised that water isentering the well bore at a second elevation. Upon continued lowering ofthe apparatus, said apparatus passes out of the zone BB and the recorderagain indicates the normal or base temperature.

Such indication continues until the apparatus l5 moves into the coolzone CC at which time the cooler temperature is recorded by an offset 24in the recording line on the tape l8. The offset 24 is opposite to theofisets 22 and 23 since the zone CC is cooler, rather than hotter, thanthe normal temperature as represented by the recording line. It is knownthat a cooler zone is created by the entrance of gas and thus thelocation of the gas strata C is determined. After passing through thezone CO, the continued lowering of the apparatus I5 to. bottom willindicate no other temperature zones since the contents of the remainderof the bore consists only of some additional oil which was caused toenter when the normal level was lowered.

From the above it will be seen that a simple and accurate method ofdetermining the location of water and gas stratas is had. The exactpoint of entry of the water and gas is ascertained and when water isshown as entering at the lower end of the well casing, as illustrated inFigure 1, it is known that either there is a water strata at this pointor the water is seepingdownwardly from a strata behind the casing. Byaccurately locating the point of entry of the water, such entry can beprevented through the usual cementing procedure. The location of thepoint of entry of the gas is also important because in most cases thegas is adjacent the oil producing formation. There are instances wherethe gas is also adjacent a water formation and in attempting to seal oflthe water, the gas and oil sands have also been unintentionally sealedoff. By knowing exactlywhere the gas enters the bore, care can be takento assure scaling 011 the water to prevent its entry without danger ofalso sealing oil. the gas formation. Thus, the method herein not onlylocates the point of entry of water but also locates the point ofingress of the gas and this is an important feature of the invention.

After the temperature measuring run is made to locate the elevations atwhich the water and gas is entering the bore, the bailer 2| may again beused to again lower the level of the fluid column whereby additionalwater, gas and oil may flow into the column. The temperature measuringapparatus is then again lowered through the fluid column and therecordings made thereby noted. It is pointed out that by the time theapparatus reaches the zones AA, BB and CC, these zones have expanded ordiffused outwardly in the fluid column due to additional entry of waterand gas. The diffusion or expansion of such zones indicates the volumeof flow of water and gas into the bore and this is recorded on the tapeHi. This recording is shown in Figure 6, the offsets 22a, 23a and 24arepresenting the zones AA, BB and CC respectively. It is noted that theoffset 23a is of greater area than the offset 22a thereby indicatingthat .the zone BB was of greater area than the zone AA. The

increased area of zone BB was caused by a greater volume of waterentering the bore from the strata B than the water entering zone AA fromstrata A. Thus, the second run of the measuring apparatus will indicatethe volume or rate of how of the water and gas into the bore at thevarious elevations.

It is apparent that the bailing operation followed by the lowering ofthe temperature measuring apparatus may be carried out as manysuccessive times as desirable. Ordinarily three or four runs are ample,although in many cases one or two runs may provide sufiicient definiteinformation. In all cases, the particular well conditions will control.

There may be instances, particularly in high temperature wells where itmay be difficult to locate the zones AA and BB created by the entry ofthe salt water; in-other low temperature wells location of the gas zoneCC may be hard to discern because of the lack of sufiicient temperaturedifierenc between the zone and the normal temperature of the fluidcolumn. When temperature conditions in the well bore are such as to makethe determination of the location of the zones AA, BB, and CCclifiicult, an auxiliary step is added to the method.

In the location of the high temperature zones, a cooling unit 25 (Figure2) is first lowered through the well fluid column in order to cool saidcolumn to a desired temperature which is known to be below thetemperature of the incoming salt water. This cooling unit may be anelongate container containing carbon dioxide or Dry Ice as it iscommercially called. This container is lowered slowly through the columnand may have to be raised and lowered several times in order to obtainthe desired lower temperature.

After the column is cooled, the temperature of the column is recorded toestablish a normal or base temperature. A bailing operation, as has beendescribed, is then carried out followed by another run of the measuringapparatus. It will be apparent that by first cooling the column byartificial means, a greater temperature differential will be set upbetween the zones AA and BB and the fluid column, whereby said zones aremore easily detected and more accurately located. Of course as has beenpointed out, any desired number of subsequent bailing operations andmeasuring apparatus runs may be made.

The COOIii'lg of the fluid column may be controlled so that the zone CCwill be of a lower temperature than the artificial zone so created sothat the zone CC will also be indicated. In such event, the gas zone CCis determined at the same time as the water zones are located.

If the normal temperature of the fluid column is low thereby making thegas zone difficult to locate, said column may be heated to accentuate atemperature difference between the gas zone and the fluid. Such heatingstep may be carried out by lowering a small pipe 26 within the well bore(Figure 2A) and introducing steam or hot water into the liquid column.When the column has been heated to the desired temperature, the

bailing operations and measuring apparatus runs, as herein beforedescribed, are made to locate the zones AA, BB and CC.

From the foregoing, it will be seen that a simple and accurate method oflocating the point of entry of both water and gas into a well bore isprovided. It is only necessary to lower the level of the fluid column topermit entry of additional well fluids and then make temperaturemeasurements. Successive measurements make it possible to not onlylocate the water and gas stratas but to also determine the rate of flowor volume of the water and gas entering the bore. The use of artificialheating or cooling means to produce a resired temperature in the fluidcolumn sets up an increased temperature differential between the zonescreated by the water and gas and the fluid column, whereby said zonesare more easily and more accurately located.

The foregoing description, of the invention is explanatory thereof andvarious types of temperature recording, bailing, heating and coolingapparatuses may be employed to practice the method, within the scope ofthe appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

l. The method of locating the point of entry of water and gaseous fluidsinto a well bore which includes, determining the temperature of the wellfluid column which is formed by the flow of fluids into the well borefrom the formation and which normally stands in the well, then removingwell fluids from the upper portion of said column to permit additionalwell fluids to enter said bore, and then determining the temperature ofthe well fluid column along the entire length of said column after theentry of said additional fluids to locate the different temperaturezones created by the entry of water and gaseous fluids whereby thelocation of the point of the entry as indicated by said zones may beascertained.

2. The method as set forth in claim 1, with the subsequent step ofremoving additional fluid from the upper end of the column, and thenagain determining the temperature of said column to ascertain thediffusion and increase of the temperature zones created by the incomingwater and gas, whereby the volume of water and gas entering the bore maybe determined.

3. The method of locating the point of entry of water and gaseous fluidsinto a well bore which includes, artificially changing the normaltemperature of the well fluid column which has entered said bore fromthe formation and which normally stands in the well bore to impart aknown temperature to said column, then removing a portion of the fluidsfrom the upper end of said column to permit entry of additional wellfluids from their respective stratas, and then measuring the temperatureof the column throughout its entire length to locate the high and lowtemperature zones created by the entry of water and gaseous fluidsrespectively, which zones are adjacent the point of entry of said waterand gaseous fluids.

4. The method as set forth in claim 3, with the subsequent steps ofagain removing additional well fluids from the upper portion of thefluid column to admit more well fluids into the bore, and then againmeasurin the temperature of the fluid column to determine the extent ofthe expansion of the water and gaseous fluid temperature zones, whichexpansion is indicative of the volume of water and gaseous fluidsentering said bore.

5. The method as set forth in claim 3, wherein the artificialtemperature changing step is a cooling of the well fluid column so thatthe hotter temperature zone created by the entry of water into the boremay be more readily and accurately detected.

6. The method as set forth in claim 3, wherein the artificialtemperature changing step is a heating of the well fluid column so thatthe cooler temperature zone created by the entry of gaseous fluid intothe bore may be more readily and accurately detected.

'7. The method as set forth in claim 3, with the subsequent steps ofremoving fluid from the upper portion of the column, and then againmeasuring the temperature of said column, said subsequent steps beingalternated and repeated a plurality of times to assure accurate determination of the elevation of the various temperature zones created bythe entry of water and gaseous fluids and also to determine the extentof the diflusion or expansion of each zone to ascertain the volume ofwater and gas entering said bore.

8. The method of locating water and gas within a well bore whichincludes, measuring the temperature of the well fluid column which hasentered the well bore from the formation and which normally stands inthe well bore to determine the norma temperature of said columnthroughout its length, bailing a portion of the well fluids from thebore to lower the level of the column and thereby cause the entry ofadditional well fluids into the bore, and then again measuring thetemperature of said column throughout its entire length after suchadditional fluids have entered the same to locate the elevation of thediflerent temperature zones created by the entry of water and gaseousfluid into the bore, which zones are adjacent the point of entry of saidwater and gaseous fluid.

the subsequent steps of alternately bailing to remove additional fluidfrom the column and measuring the temperature of said column todetermine the extent of diffusion or expansion of the temperature zonescreated by the admitted water and gas, whereby the volume of water andgas entering the bore may be determined.

11. The method of locating the point of entry of water into a well borewhich includes, determining the temperature of the well fluid columnwhich is formed by the flow of fluids into the well bore 'from theformation and which normally stands in the well, then removing wellfluids from the upper portion of said column to permit additional wellfluids to enter said bore, and then determining the temperature of thewell fluid column along the entire length of said 'column after theentry of said additional well fluids to locate the temperature zonecreated by the entry of water into the bore, whereby the location of thepoint of entry of the water as indicated by said zone may beascertained.

12. The method of locating the point of entry of water into a well borewhich includes, artificially changing the normal temperature of the wellfluid column which has entered said bore from the formation and whichnormally stands REFERENCES CITED The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 2,290,075 Schlumberger July 14,1942 2,301,326 Reistle Nov. 10, 1942- 2,366,694 -Bender Jan. 9, 1045FOREIGN PATENTS Number Country Date France NOV. 16, 1933

